you want to pull air through the filter... Get a filter that is reversible if you can. Ideally mount it inside your grow and filter your intake with a hepa filter and it will make your carbon filter last a lot longer.
It does not matter from the function of the filter or the fan. Put it all inside if noise is a concern = the quietest solution. Putting it all outside of the tent gives you the most usable grow space and perhaps easier access for emergency repair. This is the noisiest solution. A good compromise is the filter can in the tent and the motor outside. I had no choice but to put all of mine inside.
Make sure that if you push the air through your filter you have a prefilter installed in your grow space intake because when pushing air you will get no benefit from the dust cover that should come with the filter and your carbon inside the filter will fill with dust and wear out faster
The standard is filter then fan. Pulling air through the filter is a tiny/marginal bit more efficient compared to pushing air through it.. thats why the dust cover is on the outside of the filter. If you must push air through the filter.....remove the white dust cover from outside of filter,fold it in half,then slide it down the inside of filter. Or in other words the air should pass through the dust cover first before the carbon filter,in order for the dust cover to act as a dust cover. dust particals are larger than smell particals.
keep er lit